Known rotary cutting tools for performing reaming operations typically comprise a cutting head having an axis of rotation. The cutting head has a forward end and a peripheral surface extending rearwardly therefrom. The peripheral surface comprises at least two wiping pads extending rearwardly from the forward end. At least one cutting edge extends from the forward end to the peripheral surface. The cutting edge is formed at the intersection of a forward end of a chip evacuation flute and a relief surface, wherein the chip evacuation flute constitutes the rake surface of the cutting edge.
Such a construction encounters a disadvantage in that the chip that is produced during a cutting operation flows directly into the chip evacuation flute, thus lacking possibility to control the edge geometry and the chip formation, especially when different workpiece materials need to be machined. Consequently, a compromise within the cutting conditions should be made, thereby negatively affecting the productivity of the tool.
In known reaming cutting heads that are an integral one-piece solid carbide unit, the cutting edges are made at the intersection of a rake surface and a relief surface, whereby the rake surface and the relief surface are typically made by grinding at least at the vicinity of the cutting edge. At this kind of reaming cutting heads, the rake surface is an integral part of the chip evacuation flute and, therefore, the cutting edge is not provided with a chip former for controlling the chip formation.
It is an object of the present invention to provide a cutting head for a reamer that has a chip former.